The ultimate goal of this study is to develop clinical approaches to implant functional retinal tissue into the blind eye as a means of restoring vision. This will necessitate overcoming both immunobiological and neurobiological barriers. The proposed study will focus on immunologic barriers and as such is designed to extend understanding of the mechanisms of retinal graft rejection and to focus on the key elements involved in rejection. These studies should provide information for developing appropriate immunological strategies for promoting survival of retinal grafts. Three specific areas will be examined: (1) identification of immune effector cells (DH, NK, or CTL) crucial in rejection, (2) identification of lymphokines (IFN-gamma) in the intraocular microenvironment that may play a role in retinal graft rejection, and (3) identification of immunological properties of the intraocular microenvironment altered by pathological processes.